Nuprl Lemma : stable-union-decomp
∀[X,T:Type]. ∀[P:T ⟶ X ⟶ ℙ]. ∀[S:T ⟶ Type]. ∀[Q:i:T ⟶ S[i] ⟶ X ⟶ ℙ].
  stable-union(X;T;i,x.P[i;x]) ≡ stable-union(X;i:T × S[i];p,x.Q[fst(p);snd(p);x]) 
  supposing (∀x:X. ∀i:T. ∀s:S[i].  (Q[i;s;x] 
⇒ (¬¬P[i;x]))) ∧ (∀x:X. ∀i:T.  (P[i;x] 
⇒ (¬¬(∃s:S[i]. Q[i;s;x]))))
Proof
Definitions occuring in Statement : 
stable-union: stable-union(X;T;i,x.P[i; x])
, 
ext-eq: A ≡ B
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2;s3]
, 
so_apply: x[s1;s2]
, 
so_apply: x[s]
, 
pi1: fst(t)
, 
pi2: snd(t)
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
product: x:A × B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
and: P ∧ Q
, 
ext-eq: A ≡ B
, 
subtype_rel: A ⊆r B
, 
stable-union: stable-union(X;T;i,x.P[i; x])
, 
prop: ℙ
, 
exists: ∃x:A. B[x]
, 
so_apply: x[s1;s2]
, 
so_apply: x[s]
, 
so_apply: x[s1;s2;s3]
, 
so_lambda: λ2x.t[x]
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
so_lambda: λ2x y.t[x; y]
, 
pi1: fst(t)
, 
pi2: snd(t)
, 
all: ∀x:A. B[x]
Lemmas referenced : 
double-negation-hyp-elim, 
not_wf, 
pi1_wf, 
pi2_wf, 
istype-void, 
stable-union_wf, 
subtype_rel_self, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairFormation, 
lambdaEquality_alt, 
setElimination, 
rename, 
dependent_set_memberEquality_alt, 
hypothesisEquality, 
extract_by_obid, 
isectElimination, 
sqequalRule, 
productEquality, 
applyEquality, 
universeIsType, 
hypothesis, 
independent_functionElimination, 
lambdaFormation_alt, 
productIsType, 
because_Cache, 
functionIsType, 
dependent_functionElimination, 
dependent_pairFormation_alt, 
voidElimination, 
independent_pairEquality, 
axiomEquality, 
instantiate, 
universeEquality, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
inhabitedIsType, 
dependent_pairEquality_alt
Latex:
\mforall{}[X,T:Type].  \mforall{}[P:T  {}\mrightarrow{}  X  {}\mrightarrow{}  \mBbbP{}].  \mforall{}[S:T  {}\mrightarrow{}  Type].  \mforall{}[Q:i:T  {}\mrightarrow{}  S[i]  {}\mrightarrow{}  X  {}\mrightarrow{}  \mBbbP{}].
    stable-union(X;T;i,x.P[i;x])  \mequiv{}  stable-union(X;i:T  \mtimes{}  S[i];p,x.Q[fst(p);snd(p);x]) 
    supposing  (\mforall{}x:X.  \mforall{}i:T.  \mforall{}s:S[i].    (Q[i;s;x]  {}\mRightarrow{}  (\mneg{}\mneg{}P[i;x])))
    \mwedge{}  (\mforall{}x:X.  \mforall{}i:T.    (P[i;x]  {}\mRightarrow{}  (\mneg{}\mneg{}(\mexists{}s:S[i].  Q[i;s;x]))))
Date html generated:
2020_05_19-PM-09_36_17
Last ObjectModification:
2019_10_24-AM-10_17_20
Theory : int_1
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